1. Field of the Invention
The present invention relates to an attachment structure for a cam chain of a valve gear for a four-cycle engine.
2. Description of Related Art
Conventionally, a cam chain guide for guiding a cam chain in a manner that allows the cam chain to slide and a cam chain tensioner for maintaining tension of the cam chain are provided at a valve gear of a four-cycle engine (for example, refer to Japanese Patent Laid-open Publication No. Hei. 10-77905). One end of such a chain guide is supported by a bolt at an attachment member such as a crankcase etc.
A certain amount of attachment rattling occurs at the cam chain support part which causes noise to occur in accompaniment with vibrations of the moving cam chain, with this noise being particularly noticeable when the engine is rotating at a high-speed. The pressing force of the cam chain tensioner can, however, be regulated in order to prevent this noise so as to make the cam chain more tense, but this causes friction between the cam chain tensioner and the cam chain to increase which in turn influences the output of the engine.